32 research outputs found
The Renyi entropy H_2 as a rigorous, measurable lower bound for the entropy of the interaction region in multiparticle production processes
A model-independent lower bound on the entropy S of the multiparticle system
produced in high energy collisions, provided by the Renyi entropy H_2, is shown
to be very effective. Estimates show that the ratio H_2/S remains close to one
half for all realistic values of the parameters.Comment: Eur. Phys. J. C in print, 17 pages, 5 figure
Nuclear Multifragmentation in the Non-extensive Statistics - Canonical Formulation
We apply the canonical quantum statistical model of nuclear
multifragmentation generalized in the framework of recently proposed Tsallis
non-extensive thermostatistics for the description of nuclear
multifragmentation process. The test calculation in the system with A=197
nucleons show strong modification of the 'critical' behaviour associated with
the nuclear liquid-gas phase transition for small deviations from the
conventional Boltzmann-Gibbs statistical mechanics.Comment: 4 pages, 4 figure
Cross-cultural validation of the Cardiac Depression Scale in Iran
Background. The Cardiac Depression Scale (CDS) is a disease-specific instrument for measuring depression in cardiac patients. This study was designed to validate the CDS in an Iranian population. Methods. Translation and back-translation of the 26-item CDS scale was performed using recommended procedures. The Iranian translation of the CDS (I-CDS) was administered to 261 individuals in Iran, concurrently with the Beck Depression Inventory. The factor structure of the I-CDS was examined using exploratory factor analysis procedures to enable comparison with previous psychometric evaluation ofthe CDS. Receiver operating characteristic curves were used to examine the ability of the I-CDS to discriminate between categories of depression. Results. First-order exploratory factor analysis uncovered two robust factors, consistent with the second-order dimensions originally reported by the developers of this instrument. Cronbach's alpha was .88 for the total 26-item I-CDS, indicating satisfactory internal consistency of the I-CDS. Intercorrelation between the total scores for the I-CDS and BDI was .62 (p < .001). For the I-CDS cut-off of 90, the sensitivity was 85%, and specificity was 61% with a computed area under the curve (AUC) of 0.81 (95% CI, 0.76-0.87). For the I-CDS cut-off of 100, the sensitivity was 81%, and specificity was 63% with a computed AUC of 0.81 (95% CI, 0.76-0.87). Conclusion. This validation study of the Iranian version of theCDSdemonstrated that it is an acceptable, reliable, and valid measure of depression in people with heart disease.Copyright © The British Psychological Society
Nonextensive statistical effects in the quark-gluon plasma formation at relativistic heavy-ion collisions energies
We investigate the relativistic equation of state of hadronic matter and
quark-gluon plasma at finite temperature and baryon density in the framework of
the non-extensive statistical mechanics, characterized by power-law quantum
distributions. We impose the Gibbs conditions on the global conservation of
baryon number, electric charge and strangeness number. For the hadronic phase,
we study an extended relativistic mean-field theoretical model with the
inclusion of strange particles (hyperons and mesons). For the quark sector, we
employ an extended MIT-Bag model. In this context we focus on the relevance of
non-extensive effects in the presence of strange matter.Comment: 12 pages, 5 figure
Behavioural and Emotional Problems in Adolescents
BackgroundAdolescents are highly vulnerable age to psychiatric disorders. This study aimed to explore the prevalence and patterns of behavioural and emotional problems in adolescents. It was also aimed to explore associations between socio-environmental stressors and adverse outcomes.Method A school based cross-sectional study was conducted between January and July 2008. A stratified random sampling was done. 1150 adolescents in 12 to 18 year age group in grades 7 to 12 in 10 co-educational schools (government run and private) were the subjects of the study. Behavioural and emotional problems were assessed using Youth Self-Report (2001) questionnaire. Family stressors were assessed using a pre-tested 23 item questionnaire. Statistical analysis used: Univariate and multivariate analysis was done. Multiple logistic regression analysis was also done. ResultsPrevalence of behavioural and emotional problems in adolescents was found to be 30%, with girls exceeding boys in all age groups. Internalizing syndrome was the most common (28.6%) psychiatric problem. On stepwise regression analysis, a perceived lack of emotional proximity to mother had the highest odds (3.489) followed by addiction in father (2.642) and marital discord in parents (1.402). Type of school, type of family, socioeconomic status, relationship with father, mother's employment and educational status were not found to be significantly associated.ConclusionAn alarming number of our adolescents suffer from emotional and behavioural problems which have their roots in the family environment. These data suggest urgency in establishing a school based mental health service
Classification of the Nuclear Multifragmentation Phase Transition
Using a recently proposed classification scheme for phase transitions in
finite systems [Phys.Rev.Lett.{\bf 84},3511 (2000)] we show that within the
statistical standard model of nuclear multifragmentation the predicted phase
transition is of first order.Comment: 5 pages, 4 eps figures, accepted for publication in Phys.Rev.C (in
press
Liquid-Gas Phase Transition of Supernova Matter and Its Relation to Nucleosynthesis
We investigate the liquid-gas phase transition of dense matter in supernova
explosion by the relativistic mean field approach and fragment based
statistical model. The boiling temperature is found to be high (T_{boil} >= 0.7
MeV for rho_B >= 10^{-7} fm^{-3}), and adiabatic paths are shown to go across
the boundary of coexisting region even with high entropy. This suggests that
materials experienced phase transition can be ejected to outside. We calculated
fragment mass and isotope distribution around the boiling point. We found that
heavy elements at the iron, the first, second, and third peaks of r-process are
abundantly formed at rho_B = 10^{-7}, 10^{-5}, 10^{-3} and 10^{-2} fm^{-3},
respectively.Comment: 29 pages, 13 figures. This article is submitted to Nucl. Phys.
Modified Hagedorn formula including temperature fluctuation - Estimation of temperatures at RHIC experiments -
We have systematically estimated the possible temperatures obtained from an
analysis of recent data on distributions observed at RHIC experiments.
Using the fact that observed distributions cannot be described by the
original Hagedorn formula in the whole range of transverse momenta (in
particular above 6 GeV/c), we propose a modified Hagedorn formula including
temperature fluctuation. We show that by using it we can fit
distributions in the whole range and can estimate consistently the relevant
temperatures, including their fluctuations.Comment: Some misprints corrected, references updated. To be published in Eur.
Phys. J. C (2006
Canonical Strangeness and Distillation Effects in Hadron Production
Strangeness canonical ensemble for Maxwell-Boltzmann statistics is
reconsidered for excited nuclear systems with non-vanishing net strangeness. A
new recurrence relation method is applied to find the partition function. The
method is first generalized to the case of quantum strangeness canonical
ensemble. Uncertainties in calculation of the K+/pi+ excitation function are
discussed. A new scenario based on the strangeness distillation effect is put
forward for a possible explanation of anomalous strangeness production observed
at the bombarding energy near 30 AGeV. The peaked maximum in the K+/pi+ ratio
is considered as a sign of the critical end-point reached in evolution of the
system rather than a latent heat jump emerging from the onset of the first
order deconfinement phase transition.Comment: 20 pages, 2 figures; typos corrected, 2 references added, minor
corrections in text and figure